The australian naval institute



Download 0.86 Mb.
Page3/10
Date conversion15.05.2016
Size0.86 Mb.
1   2   3   4   5   6   7   8   9   10
THE INTEGRATION OF

HELICOPTERS INTO RAN

AIR-CAPABLE SHIPS

By Commander I.M. Mclntyre RAN

For many years now the Royal Australian Navy has successfully operated various helicop­ter types from the carriers SYDNEY and MELBOURNE, on both an embarked squadron and deployed flight basis More recently. Bell 206B Helicopters have been operating from HMAS MORESBY in support of survey tasks, and utility helicopter operations have been carried out from HMAS STALWART, albeit in a very ad-hoc fashion relative to maintenance and logistic support.





RAN Air-capable ships 1980

We have now entered an era of increasing deployed helicopter activity in the Fleet. We are planning to embark utility helicopters in HMAS TOBRUK to assist in the ship-to-shore movement task; utility hefos will provide the Vertrep facility in SUCCESS and eventually the second AOR; heli­copters with a unique weapon and sensor equip­ment fit will embark in the four FFGs. and ultimate­ly in the Follow-on Destroyers. It may be that we have also to plan for RAN helicopters to emark in the Australian Antartic ship. Therefore, we will be expanding the deployed helicopter concept in ships, other than the carrier, from two vessels at present to eight in 1985, and sixteen in the 1990s.

It is a relatively simple matter to appreciate the increase in ship/helicopter combinations which I've described. What is not generally appreciated by personnel outside the immediate sphere of Fleet Air Arm activity, however, is the vast amount of forward planning required to successfully integrate helicopters into ships. The helicopter should not be seen as a totally separate entity (or worse, an encumbrance) on the aft deck of a ship, capable of moving on and off at short notice, and requiring only extra fuel to keep it going. The modern helicopter is an extremely complex and sensitive machine, requiring much detailed and well-planned support. On a small ship, with a very confined and moving flight deck, with limited servicing and maintenance facilities, and the hazards of winds, seas and spray, it is operating in the harshest and most inherently dangerous environment that it possibly can. Thus the interface between aircraft and ship must be fully planned for, and the combination carefully tested so that safe operating limits can be determined, and any deficiencies in the interface rectified before service use of the helicopter is commenced.

The RAN is only now beginning to also appreciate that a lot of careful design must go into even the simplest of the aviation facilities in an air-capable ship. For instance, a major flight deck repair to STALWART had to be carried out recently, following the discovery of damage

THE AUTHOR

CMDR Ian Mclntyre |oined Ihe Navy as a Cadet Midshipman in 1954. and subsequently specialized as an Air Engineer Officer and Pitol Between 1968 and 1972. he ludher qualified as a Flying Instructor and Engineenng Test Pilot He has served in HMAS MELBOURNE, and at Ihe Naval Air Station. Nowra Other postings have included the RAN Aircraft Maintenance & Flight Trials Unit and Ihe Australian Embassy in Washington, as well as sen/ice with the RAAF and USN He is currently working in Navy Office Canberra as the Director of Naval Aircraft Engineering

This article is reprinted wilh Ihe permission of the Editor of Ihe fleet Maintenance Bulletin

Journal ot the Australian Naval Institute Page 9

caused by the high wheel loads of Wessex and Sea King helicopters. Flight decks in themselves are relatively simple structures. However, ship-borne helicopters of the Seahavvk size may weigh as much as 9000 kg. This load can be multiplied several times due to ship heave, and even more for the dynamic landing case Most of the load is distributed through two main wheels, and thus point or footprint loads on the plating as well as distributed loads between supporting beams are extremely high, therefore adequate design is essential. The matter of adecuate dimensional clearances must be addressee early in the ship/ helicopter compatability study, both on the flight deck for the rotors engaged and flying cases, and for movement into and securing within the hangar. Clearance criteria have been established through trials and much operational experience, in the USN and RN.

In the case of the USN, such criteria are promulgated together with minimum physical standards for all the aviation facilities required on air-capable ships in the Naval Air Systems Command Helicopter Facilities Bulletin No.l.D'. Features and facilities such as lirefighting and fuel systems, tie-down fittings, maintenance facilities, deck markings, power supplies, lights, safety nets, hangar drainage and sealing provisions are only a very few of those specified in the Bulletin. As the RAN did not have a similar specification, was purchasing American air-capable ships and because current Defence guidance indicates that we should pursue interoperability with the USN as a prime requirement in any system developed to

support operation of helicopters from our ships, it was decided earlier this year that we would adopt the Bulletin as a base-line document for our own use. The RAN ship aviation facilities certification authority will of course be able to provide waivers where the facilities in existing ships or those of a non-USN design do not meet the specification but are considered safe or suitable after full objective assessment. The long-term aim. however, is to standardise markings, lighting and other aids and facilities to provide the greatest degree of oper­ating safety and to enhance cross-operating capabilities with the USN.

An interface aspect of particular significance in the case of fighting ships (rather than support ships such as MORESBY. STALWART or SUCCESS) is the capability for the helicopter to be rapidly secured on touchdown, and moved into and out of the hangar under moderate or high ship motion conditions. The FFG helo will be an inte­gral part of the ships weapon system and must therefore be capable of being launched and re­covered during the heat of the battle Helicopter launch and recovery requirements must not preclude ship manoeuvenng which may be essential in the operational situation, and weather conditions and sea states (other than the extreme) must not inhibit use of such an important element of the overall ship weapon system. In this regard, the British and French have developed a deck grid locking facility called Harpoon, which physically holds the aircraft to the grid after the probe under the aircraft is lowered. The Americans, on the other hand, are developing the Canadian Beartrap design for use on the LAMPS

1985





















f XNTARCTII

SHIP

/

RAN Air-capable ships, 1985.

Page 10 — Journal ol the Australian Naval Institute

/// helicopter (the Seahawk); this facility is called RAST (Recovery Assist, Secure and Traverse) which will guide the helicopter to the deck, positively lock it down, and finally traverse the aircraft in a rail system into the hangar. The system has been designed to allow safe Seahawk operations in a small ship such as the FFG-7 class, in up to sea state 5.

A major decision in regard to RAST fitting must of made by the RAN in the near future. The system is extremely expensive, and there are no provisions for it in the first three of the our FFGs. It is tailor-made for the Seahawk airframe, and thus adoption of the system for the RAN is contingent on selection of the Seahawk for the FFG helo mission It has been suggested that a much cheaper alternative would be fitment of a Harpoon deck grid and a cable traversing system. It must, however, be appreciated that integration of a harpoon system into a helicopter not initially designed for such would involve an extremely expensive and lengthy research and develop­ment programme; the central fuselage structure would require re-design so that heavy lateral and longitudinal loads could be diffused, and hydraulic and electrical subsystems would have to be in­stalled. So in effect we have got to bear a massive cost in retrofit of RAST if indeed the Seahawk is selected as the FFG helo, or accept a much lower operating capability due to the degraded deck interface.

The importance of particular helicopter characteristics and equipment required for small ship operation has also become more obvious to

RAN authorities in recent years. Commonality for basic helicopter types to carry out separate missions for both Navy and Air Force has become an important issue in current defence planning. In this respect, unique Navy requirements for small ship operation may become over-riding consider­ations in a common type selection. For instance, a helicopter expected to operate successfully from an air-capable warship should incorporate features such as rapid control response (dictating an articulated or rigid rotor system), wheeled undercarriage, rotor brake, blade droop stops (the latter two being used to minimise rotor control problems and blade sailing under high wind con­ditions), blade folding for containment in small hangars), strengthened tie-down fittings, clear downward vision and windscreen wipers, minimal use of highly corrosive material, marmised engines, a hold-down facility if possible, flotation equipment and so forth. It could be argued that the Bell-206B, without most of these features (partic­ularly with a low response teetering rotor head and skids) would be a very poor performer on an air-capable ship, when in fact it is used quite successfully on MORESBY.

The truth is that many of MORESBY'S oper­ations are tailored to ensure complete safety of the aircraft for launch and recovery, if conditions are not close to perfect, the ship may for example proceed to the lee of land to find ideal sea and wind conditions. This would most definitely not be the case for fighting ship helicopter operations, and this must be borne in mind at the outset when planning for aircraft type selection.





iMinnwiiMdi




RAST system tayout.

Journal ol the Australian Naval Institute — Page 11

Another of the important aspects of success­ful integration of helicopters into air-capable ships is the carrying out of comprehensive flight trials prior to full service deployment of a ship s heli­copter flight. The problems of flying a helicopter from a small ship are a direct result of:

a. the small and confined area available for
take-off and land;


b. turbulence caused by the ship s superstruc­
ture:


and c a moving landing platform oue to ship motion.

In order that safe, repeataole operations can be carried out, ship movement limits and a wind limit envelope must be defined. This is achieved through carefully planned builc-up flight trials; the helicopter is flown by a test piloi with experience in establishment of such limits and comprehensive instrumentation is used. Combinations of wind-speed and direction, ship movement and aircraft weight are progressively increased during many landings, until limit points based on the following four criteria are reached:

a. any aircraft control margin (for cyclic, collec­
tive and pedal controls) is reduced to 10%
remaining;


b. A 10% power margin emains for night
landings or 5% for day landings;


c. Pilot workload becomes excessive;
or


d. an aircraft structural limit is approached.
Thus both the aircraft ana the ship have to be


instrumented to provide such parameters as separate helo flight control positions, tail rotor pitch, engine torque, normal acceleration of aircraft and touch-down rate; on the ship side, heavy and sway; relative windspeed and direc­tion; and pilot's qualitative comments. This in turn requires that the sensors and data recorders are installed in both the aircraft and the ship, and operated on a commontime oase. Hundreds of landings are made, and a lot of data analysis is then required to establish the final ship/helicopter type operating limitations. Of course, the quantita­tive data must be continually matched against the test pilot's qualitative assessments, the latter being based on a standard plot rating scale. All these techniques and procedures have been developed by the RN and U5N, and have now been adopted by the cognisant RAN agency, which is the Aircraft Maintenance and Flight Trials Unit (or AMAFTU) at Nowra.

It is the intention that at least one fully qualified rotary wing test pilot capable of running an interface trial as described will always be posted to the Trials Unit. At this time, specialised test equipment is being assembled and tested at AMAFTU in preparation for the next RAN First of Class helo interface trials to be progressed (le a number of helicopter types :o be cleared from TOBRUK). It should be borne in mind, of course,

that the ship's aviation facilities are also fully tested, and checked against minimum prescribed standards, during First of Class trials.

Any large or medium-sized helicopter is a maintenance-intensive vehicle and it should be appreciated that this maintenance must be carried out under generally cramped and difficult conditions. Hence there is the need for a lot of detailed forward planning to ensure that best use is made of the limited space available. Stowage of ground support equipment, tools, publications etc. on the deck, in dedicated storages and on bulkheads has got to be planned in line-out drawings, and proved through actual configur­ation trials; space for administration of tool control, maintenance scheduling and documen­tation control must also be planned for. Although helicopters are normally serviced and maintained onboard small ships to organisational level only, with repair by replacement, space for simple mechanical workbenches and avionic equipment test benches has also to be provided. Some ser­vicing and maintenance activities must be earned out under conditions unique to small ship oper­ations — heavy components may have to be changed under ship motion situations; mainten­ance operations such as borescope inspections, vibration measurement and analysis and so forth are complicated by restricted space conditions and generally poor light in the hangar and main­tenance spaces. Inspection and control of corro­sion assumes particular significance in the salt — laden environment of a small ship at sea. Corro­sion prevention and rectification is time-consuming, making further demands on the overall maintenance effort.

An embarked helicopter logistic support policy is also currently being progressed. With limited aircraft support equipment and spares assets, and the ever-present limitations to spares funding, the RAN can not hope to stock each air-capable ship with a full range of helicopter equipment and spares, regardless of whether the aircraft is embarked or not. as is done in the RN. Thus effort is now being put into the devising of portable Pack-up' support kits, tailored to an overall logistic support requirement in turn based on number of aircraft embarked; expected days away from port; and flying rate of effort.

Such a system is currently used by the USN. where the number of air-capable ships is far in excess of the number of detached flights embarked at any one time. Storage is based on a number of modular cabinets which may be air-or ground-transportable, and can be arranged by drawer size to provide maximum spares storage density, thus minimising overall space require­ments once placed in the ship. Again, long-range planning is necessary to ensure that adequate space for the pack-ups close to or in the hangar is allocated; much effort is required in establishing

Page 12 — Journal ot tne Australian Naval Institute










Floating Flight Deck Training Aid (FFDTA) of the Royal Navy.

the Outfit Allowance Lists for each individual pack-up requirement. Finally, pack-up configur­ation trials are necessary prior to service use to devise the minimum-sized pack-up unit.

As I intimated earlier, small ship helicopter operations are probably the most inherently dangerous aircraft operations taking place today. To minimise the potential for catastrophic acci­dents involving both aircraft and parent ship, aircrew and flight deck personnel must be trained to exceptional skill levels in as realistic an environ­ment as possible.

A shore dummy deck can be used to work up crews during initial training, but such a facility has limitations, and a natural progression of this concept is a floating flight deck training aid (FFDTA). Some years ago, the RN converted a large aircraft lighter into such an aid, and have realised enormous benefits in use of the facility. It is planned that the converted lighter be replaced with a purpose-built vessel in the near future.

It has been assessed that a slightly less sophisticated but similar facility for our navy is now justified, and a Naval Staff Requirement is currently being raised. The FFDTA is going to be built in Australia, and will provide all the training facilities of a representative ship's flight deck. It is planned that it be moored in Jervis Bay close to RANC, and capable of being swung to provide variable wind direction conditions. The low swells in the bay will cause some deck movement which will provide added realism. The facility will be used to work up flight deck crews in aircraft handling, lashing and unlashing, firefighting, helicopter directing, vertrep and refuelling

practice, weapon loading drills etc, by day and night. It will also of course, provide a realistic environment for pilot flight deck familiarisation and currency training at a fraction of the cost which would be incurred were actual air-capable ships to be used on a dedicated basis for basic training.

Other aspects of training for our air-capable ships expansion are being addressed.

A Flight Deck Training Officer's billet has just been established at the Training School at NAS NOWRA; the Flight Deck Officers' training syllabus is being upgraded whilst sailor trade cross-conversion courses will be established.

It has got to be appreciated that air technical sailor shortages exist and that accommodation space for detached flight personnel on small ships is limited. Thus it is necessary that sailor trade skills and capabilities are broadened within the total numbers constraint for any one ship s flight. For instance, air technical personnel other than weapons specialists will have to form the quick-reaction weapons loading team; sailors of the ATWL (or air electrical) category may be required to carry out organisational level maintenance on avionic equipment normally under ATC (or radio) category cognizance.

Action is being taken to upgrade other aspects of the infra-structure required to support the air-capable ship aviation effort.

An aircraft/ship integration planning cell is being established within Navy Office. The team will consist of five personnel initially, possess both operational and technical expertise, and be responsible to the Director of Naval Aircraft

1   2   3   4   5   6   7   8   9   10


The database is protected by copyright ©essaydocs.org 2016
send message

    Main page